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The sternum connects with the ribs forming the front of the rib cage. Without the sternum there would be a big hole in the front of your chest. The sternum plays an important role in protecting the heart, lungs and major blood vessels from damage.

Close Up of Sternum - Anterior (Front) and Lateral (Side) View

The diagram on the right shows a front and side view of the sternum. From the front, the sternum is shaped somewhat like a dagger.
From the side, the sternum appears as a long, flat bone with a outward curvature.

The sternum consists of 3 parts: the manubrium, the body of sternum or gladiolus, and the xiphoid process.

The top of the sternum, or manubrium, connects with the clavicles or collarbones. It also connects to the 1st pair of ribs. The body of the sternum connects with the next 6 pairs of ribs. Together, these 7 pairs of ribs are known as the true ribs.